Well formation packer assembly for measuring gas-oil ratios



Oct. 13, 1953 s D. BARTON 2,555,033

WELL FORMATION PACKER ASSEMBLY FOR MEASURING GAS-OIL RATIOS Filed June4, 1949 INVENTOR. GERALD D. BARTON m'm y llw ATTORNEY Patented Oct. 13,1953 WELL FORMATION PACKER ASSEMBLY FOR MEASURING GAS-OIL RATIOS GeraldD. Barton, Tulsa, Okla., assignor to Stanclind Oil and Gas Company,Tulsa, Okla., a corporation of Delaware Application June 4, 1949, SerialNo. 97,110

(Cl. 'i3155) Claims. 1

The present invention relates to a novel .type of well formation packerassembly. More particularly, it pertains to a novel packer assemblyhaving by-pass and valving means suitable for use in wells such as, forexample, oil wells in which the ratio of gas to liquids produced isquite high.

An object of my invention is to provide a packer capable of readilymaintaining its original position of setting when employed in wellshaving a high gas to oil ratio. It is a further object of my inventionto provide a packer suitable for use in wells having a high gas to oilratio wherein the volume of gas escaping from the packed oil zone of theproducing formation across the packer can be measured as it passesthrough the latter. A still further object of my invention is to providea packer capable of separating in a satisfactory manner oil from gas,both of which are being produced from the same restricted zone,

by allowing the gas to escape from said zone through a conduitcommunicating with the zone above and the packed ofi zone immediatelybelow the packer, the passageway being capable of opening and closing ata predetermined level of the liquid in the packed off zone.

Packing elements of the type contemplated by my invention are useful incarrying out various operations in the presence or high gas pressures ina well bore. For example, in identifying fluids and their respectiverates of production in a restricted zone, such as are described andclaimed in copending application U. S. S. N. 97,764, filed June 8, 1949,by Ralph E. Hartline and Joseph D. Eisler, the device or the presentinvention may be advantageously employed. According to the aforesaidcopending application well fluids may be identified and the respectiverates at which these fluids flow may be determined by placing a stringof vertically spaced electrodes in a packedoff zone in the well bore.The rate oi flow of oil or water is measured by following the movementof the oil-water interface in the zone defined by two packers. The totalfluids produced in the particular zone investigated is computed by theaid of a flow meter located in the tubing connecting the packers andwhich measures only the product from said zone. Production, preferablyat a constant rate, is commenced and the rate of rise or fall of theoil-salt water interface is determined by observing the time at whichthe interface passes the electrodes. It the well fluid in the test zoneis principally salt water at the time of setting the packers, theoil-water interface is high in the zone, initially. The lnteriace thenmoves downward during the test period if oil production occurs, and itsrate of fall establishes the oil production rate if the bore holediameter is known. By determining the total production passing throughthe flow meter and subtracting the production rate of the oil, asdetermined above, the production rate of the salt water can beascertained. Thus, in systems for identifying and determining productionrates of well liquids by gravimetric collection between packers in arestricted zone of an oil well, there is placed a differential pressureacross the top packer equal to the static head resulting from thedifference in density between the original fluid in the packed off zoneand the fluid being produced plus the differential pressure resultingfrom the flow of the produced fluid. When the fluid collected under theupper packer is crude oil, the resulting differential pressure is notexcessive and the requirement that the packer confine the produced fluidagainst this differential pressure does not impose too great alimitation upon its operation. The requirements imposed upon the upperpacker are, however, much more severe when gaseous products producedfrom the packed of! area accumulate under the packer. The greaterdensity dliierence results in a markedly higher packer load imposed bythe differential pressure thus produced. The term "density" as usedherein reiers to the differential pressure exerted on the underneathside oi packer 2 produced by the hydrostatic head of the column of oilstanding in tubing 4 on the column of oil and gas in the packed of! zonewith which the oil in tubing 4 is in communication through aconventional entrance port. Owing to the presence of gas in the columnof fluid confined by the packed oil zone, the density of that column isless than the column 01' oil standing in the tubing. It is thisdiiierence in density of these respective columns that produces theabove-mentioned diiierential pressure. The identification oi the wellfluids and the determination or their respective production rates alsobecomes more complex by the creation 0! the gas-oil and oil-waterinterfaces. The gas-oil interface cannot be identified by means of theusual conductivity measurement systems. Moreover. it is the relativelymore valuable liquid volume whose production rate is generally desiredto be ascertained. With apparatus previously employed for measuring theproduction rates of well fluids in a packed 0!! zone, much dlfllcultyhas been encountered where high gas to oil ratios prevail. Under suchconditions the gas pressure tends to build up until the upper packerbecomes dislodged from its original setting thereby allowing a mixture01 gas and entrained oil to pass upwardly around the packer into theunrestricted zone the well bore. Obviously, under circumstances such asthese, it is impossible to measure accurately the oil production rateirom the test zone.

In order to reduce the packer load to a minimum in wells having a highgas to oil ratio and to allow measurement 0! the more valuable oil; I:have devised a packing unit assembly suitable ior hy-passing producedgas across the. packer. Thus, my invention contemplates the utilizationoi a conduit in communication with. the zonev above the packer and thetest zone-immediately below the packer, said conduit being capable ofopening and closing at a predeterminedlevel otthe liquid in the testzone. The opening and closing oi the conduit may be effected by anyoiseveral known methods such as by the utilization of a-llquid levelresponsive means, ior'example, a hoot actuated valve. Such valve remainsin a closed position as the result at the buoyant force exerted on thefloat by the oil. The corresponding force exerted by the gas, however,is insufficient to maintain thevalve closed andithe gaseous products areaccordingly vented through the packer into the unrestricted zone abovethe unit until the gasoil interface rises to lift the float and closethe valve. By employing a float valve, 3

for example, of the snap action" type. in which a definite diflerentialmotion of the float is required between iull open and completely closedpositions, it is possible to obtain. an approximate quantitativemeasurement oi the vented gaseous products. A switch attached to thevalve can then transmit a signal through the switch circuit to asuitable recording means whereby estimation can be made or the volume ofproduced gas.

A preferred embodiment of the packing unit of my invention may bedescribed with more particularity by reference to the accompanyingdrawing in which a packer 2 isdisposed about a well tubing 4 havingmounted therein a passageway or conduit 6. A :loat actuated valveassembly is shown attached to the lower portion of conduit. 6 providedwith seat 8; The buoyant force of the-liquid oil applied to float,lfl-attached to arm 12, which is hin-gedly mountedrto welltubing Iat-ll, functions to close conduits by'means of valve stem IS. Thecorrespondingiiorce exerted'bythe-gas insufliclent to maintainvalve seat8 in the "closed" position, and, as a result. gaseous products from thetomatlonare vented into the well bore above packer t'through: port [8 ofconduit 8. Gaseous products continue to-be vented into the well boreuntil thegas-oilintel-face rises to lift float i0- bringingvaive seat 8and'vaive stem it again into sealing'relationship. By knowing the volumeof gas required'to lower the liquid-gas interface so that the floatvalve stem IG- disengages seat 8, and by knowing the volume of gasremaining atter'said gaoandiliqulzi interface causes the now valve stemis to disengage seat 8. the gas production rate can be calculated. Thus,the number oi times matsthe sys- 'tem opens and closes per minute canreadily be observed on recording ammeter ld which' indicates completionand breaking oi circuit 22 through electrical contacts Hand 28. Thelengt of time the circuit remains open and ciosedimay be recorded on asuitable time-driven recording roll 28 by needle 30 actuatedby recordingommeter 20. Uniform movementoiroll-It is accom- 4 pllshed by knownmeans, such as clock mechanism 32.

When employing a packing element oi the type contemplated by myinvention in isolating an intermediate well bore zone, it is desirableto provide exhaust ports in the well tubing above and below the packedoflf zone-iniorder that gas or oil produced in the unrestricted zones ofthe well bore can be withdrawn therefrom into the pro- 1 duction stringand thereby avoid undue stress on the packing units.

It is apparent that various modifications can be made in theabove-described apparatus without departing irom. the scope of myinvention. In general, it may be said that the apparatus hereinset forthis applicable to the solution 02 problems created by the presence ofexcessive volumes 01 gas in a web bore wherein it is de sired either toqualitatively separate gases from liquids or to measure the productionrate of such ases.

What I-claimis:

1. In a wellpacker. assembly for handling gas in a packed ofi zone ofswell bore producing oil and gas, the combination cOmprisingJa welltubing, a packing element disposed about said tubmg, there being anopen-ended conduit communicatin with the zone above. and with. saidpacked off zone-immediately below said packing element, and a liquidlevel responsive vaivemeans attached to said tubing anmadaptedto closethe end of said conduit communicating: with: said zone immediately belowsaid packing element at a predetermined liquid level in said. packed onzone.

2. In a well packer assembly for handling. gas in a packed oiI zone 01 awell bore producing oil and gas, the combination comprising awell tubing, a packing element disposed aboutsaid tubing, there being anopen-ended conduit in. said tubing communicating with the-zone above andwith said packed of! zone immediately below said packing. element, and afloat actuated valve means. attached to said tubing and adapted to closethe end. or said conduit. communicating with said zone immediatelybelow. said packing element at a. predetermined liquid level in saidpacked oi! zone.

8. A. packer. assembly for handling: gas im a packedofl zone. of. a wellbore producing oilsand gascomprising a well tubing, 9. packingelementdisposed. about sairhtubing. there bein -an openended conduit. insaidtubing. communicating with the zone; above and. with saidpackedi of!zoneimmediately below said packing element, means including liquid.level. responsive valve means attached' to: saidtubing and adapted toopenand close the. end-oi said conduit communicating with thezoneirnmediatebr-beiowsaid pack-- m8. element at a predetermined liquidlevel. in midpacked 0.11 none.

4;. Inc packer assembly tor-handling gas in a packedaoii zone'ot. awellzbore producing oil and gas. the combinationicomprising aweiltubing; a

packing element disposed-about said tubing. there beinganopen-endedioonduit insaidtubingcommunicating with the zone above andwith said packedoil zonczlmmediately below saidpacking element, a.liquid level responsive valve means atbachedto said tubing and adaptedtoclose-the end oisaid conduit communicating with; the zone immediatelybdow said packing. element at a predetemiinedlliquid leveizinasaidpackedioit zone, a circuit including a switch connectedto and ao- 5tuated by said valve means which closes said circult simultaneously withthe closing 01 said liquid level responsive valve means, and means forproducing an indication of electrical current flow in said circuit.

5. In a packer assembly for handling gas in a packed 01! zone of a wellbore producing oil and gas, the combination comprising a well tubing, apacking element disposed about said tubing, there being an open-endedconduit in said tubing communicating with the zone above and with saidpacked oi! zone immediately below said packing element, a float actuatedvalve means attached to said tubing and adapted to close at apredetermined liquid level in the packed ofl zone of a well bore the endof said conduit communicating with the zone immediately below saidpacking element, a circuit including a switch connected to and actuatedby said valve means which closes said circuit simultaneously with theclosing 0! said valve means, and means for producing an indication ofelectrical current flow in said circult.

GERALD D. BARTON.

Reterences Cited in the file of this patent UNITED STATES PATENTS

